One of the easiest ways to provide your photo to be embedded into a post is to upload it onto an image hosting site such as Photobucket, Flickr, etc. That should be pretty straight forward, and the individual sites will give instructions on how to get your photos uploaded to their site when you sign up.

Once your picture has been uploaded, find its image location address (URL) by right clicking on the image and copying the image location. The URL will look something like:

http://somepicturesite.com/yourpicture.jpg.

Some sites may even provide the appropriate HTML code in a text box below the photo for your convenience. It will be the one that begins with a href=... (This code looks different than the code below, because it will actually produce a picture link instead of just a picture.)

Let's say, as an example, that the address of the picture you want to post is http://somepicturesite.com/yourpicture.jpg

To embed the picture into a post, use the command:
img src="http://somepicturesite.com/yourpicture.jpg">;
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If your picture is too large to fit nicely into the text page, you can add a width attribute.

The command with the width attribute would look something like:
img src="http://somepicturesite.com/yourpicture.jpg"; width=600>
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Note that I had to use special characters to get the commands above to show up here without turning into pictures, but you can use them as shown (but with the correct image web address).

I have found tinypic.com the easiest.

Put the picture on your computer and save it to your desktop. Go to tinypic.com, upload your picture and choose the FIRST line of html. Right click on it and choose 'copy'.

Come back to your thread and right click and choose 'paste'. When you click on 'preview', your picture will show up. If it doesn't, try again.